Return-Path: linux-nfs-owner@vger.kernel.org Received: from fieldses.org ([174.143.236.118]:55590 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933271Ab3JOT3g (ORCPT ); Tue, 15 Oct 2013 15:29:36 -0400 Date: Tue, 15 Oct 2013 15:29:09 -0400 From: "J. Bruce Fields" To: Christoph Hellwig Cc: Al Viro , "J. Bruce Fields" , linux-nfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH 4/4] dcache: don't clear DCACHE_DISCONNECTED too early Message-ID: <20131015192908.GB10128@fieldses.org> References: <1378579561-26868-1-git-send-email-bfields@redhat.com> <1378579561-26868-5-git-send-email-bfields@redhat.com> <20130909004647.GK13318@ZenIV.linux.org.uk> <20130909204655.GA10599@fieldses.org> <20131011160237.GA21258@fieldses.org> <20131012084235.GB5649@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20131012084235.GB5649@infradead.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Sat, Oct 12, 2013 at 01:42:35AM -0700, Christoph Hellwig wrote: > On Fri, Oct 11, 2013 at 12:02:37PM -0400, J. Bruce Fields wrote: > > But just for fun--I did some cleanup and fixed some other quadratic > > behavior here and can notice a difference on lookups of very deep > > subdirectories. > > > > For example I'm seeing an uncached lookup of an 8000-deep directory > > taking about 6 seconds, and can get that down to a tenth of a second. > > > > I'm not sure yet if the difference on less extreme examples is really > > significant, I need to experiment some more. > > > > I'll do some more review and post patches and results. > > This sounds like and awesome improvement. Nobody should be nesting that deep, but maybe it's useful to have the insurance against bad behavior anyway. > How much code do you have to > add for it? fs/exportfs/expfs.c | 224 ++++++++++++++++++++++++++-------------------------- 1 file changed, 112 insertions(+), 112 deletions(-) But maybe I removed some necessary complication. I'll post the patches.... --b.